The subject matter herein relates generally to electrical connectors that have pairs of signal conductors configured to convey differential signals and ground conductors that control impedance and reduce crosstalk between the pairs of signal conductors as well as to provide a reliable ground return path.
Communication systems exist today that utilize electrical connectors to transmit data. For example, network systems, servers, data centers, and the like may use numerous electrical connectors to interconnect the various devices of the communication system. Many electrical connectors include signal conductors and ground conductors in which the signal conductors are arranged in signal pairs for carrying differential signals. The ground conductors are positioned between the signal pairs to control impedance and reduce crosstalk. Each signal pair may be separated from the adjacent signal pairs by one or more ground conductors. For example, the signal and ground conductors may be arranged in a ground-signal-signal-ground (GSSG) pattern.
There has been a general demand to increase the density of signal conductors within the electrical connectors and/or increase the speeds at which data is transmitted through the electrical connectors. As data rates increase and/or distances between the signal pairs decrease, however, it becomes more challenging to maintain a baseline level of signal quality. More specifically, in some cases, electrical energy that flows along the surface of each ground conductor may form a field that propagates between the ground conductors. For example, the ground conductors that flank the signal pair in the GSSG pattern may couple with each other to support an unwanted propagating signal mode. The unwanted electrical propagation mode may then be repeatedly reflected, such as between two PCB ground planes, and form a resonating condition (or standing wave) that causes electrical noise. Depending on the frequency of the data transmission, the electrical noise may increase return loss and/or crosstalk and reduces throughput of the electrical connector.
To control resonance between ground conductors and limit the effects of the resulting electrical noise, it has been proposed to electrically common the separate ground conductors using a metal conductor or a lossy plastic material. The effectiveness and/or cost of implementing these techniques is based on a number of variables, such as the geometry of the connector housing and geometries of the signal and ground conductors within the electrical connector. For some applications and/or electrical connector configurations, alternative methods for controlling resonance between the ground conductors may be desired.
Accordingly, there is a need for electrical connectors that reduce the electrical noise caused by resonating conditions in ground conductors.